Signage is common for basic communications and is the most popular form of advertising worldwide. Advertising signage, for example, is extremely effective in the form of illuminated point of purchase signs, commonly found in airport terminals, bus and train stations, sporting arenas or stadiums, convention centers, hotels, and other public walkways, or places of high pedestrian traffic. These signs are decorative multi color arrays and are retained in outwardly protruding illuminated cabinets or light boxes, the cabinets mounted on a wall, or other stable support structure, for example, a balcony front at a sporting arena or stadium.
An exemplary sign 20 of overall length (L) and overall depth (D) is mounted on a wall 21, as illustrated in FIGS. 1, 2a, and 2b. These drawing figures are diagrammatic, to illustrate the structures detailed below and accordingly are not to scale. This sign 20 includes a cabinet 22 (also known as a light box), of sheet metal or the like, with a body 24, having rear 25, side 26a, 26b, upper 27 and lower 28 walls and an open front (side). The body 24 may also include borders 29 (continuous or non-continuous along the periphery of the open side of the cabinet body 24), affixed to the cabinet walls 26a, 26b, 27, 28 by conventional mechanisms, to assist in preventing the graphic unit 32 from moving (or being pushed) into the cabinet 22. The borders 29 preferably have their outermost surfaces flush with the edges of the side 26a, 26b, upper 27 and lower 28 walls at the open side of the cabinet body 24, and may include an indented section (not shown), typically referred to as a screw trough, for receiving screws 35, rivets or the like.
The cabinet 22 encloses lights, for example, 800 milliamp (ma) fluorescent tubes 30 (also referred to as fluorescent bulbs or fluorescent lamps), of lengths ranging from eighteen inches to ten feet (46 cm to 305 cm), and diameters typically approximately 1.5 inches (3.81 cm), or other suitable illuminating devices. In this sign 20, the fluorescent tube arrangement(s) are exemplary, and additional similar arrangements within the cabinet 22 are permissible if desired.
A graphic unit 32 is positioned in a retainer 34 (frame). This retainer 34 holds the graphic unit 32 in place against the cabinet body 24, as the graphic unit 32 abuts the edges of the side 26a, 26b, upper 27 and lower 28 walls and the borders 29. The retainer 34 is made of individual members 34a, preferably four (one for each cabinet periphery side), each member having lips 34b that abut the edges of the side 26a, 26b, upper 27 and lower 28 walls when the sign 20 is properly formed. Each of the members 34a that form the retainer 34 attach to the cabinet body 24 by clamping screws 35, conventional threaded screws received in openings in the cabinet body 24, latches, hinges, or other similar attachments. When any retainer member 34a is removed from the cabinet body 24, the graphic unit 32 can be removed by being slid therefrom. Other conventional retainers for the graphic unit 32, such as friction fitting members, are also permissible.
The graphic unit 32, typically includes a graphic 36 (typically a transparency), sandwiched between a diffuser panel 38 (typically a translucent polymeric or plastic sheet), oriented rearward toward the cabinet rear wall 25 and a protective cover member 40 (typically a transparent or clear polymeric material), held in contact by the sandwich arrangement. The cabinet 22 has an internal length (1), from the innermost surface of the sidewall 26a to the innermost surface of the opposite sidewall 26b, and an internal depth (d), from the rear wall 25 to diffuser panel 38 (alternately expressed as the distance from the rear wall 25 to the plane formed by the edges of the side 26a, 26b, upper 27 and lower 28 walls along the open side of the cabinet body 24).
In the sign 20, the internal cabinet length (1) is 10 feet (3.04 m) or less, as it includes a single fluorescent tube 30 or tubes, depending on the sign height, that span or spans the entire internal cabinet length (1). This fluorescent tube 30 is received in electrical connection and coaxial alignment with the respective sockets 42a, 42b (the center point of the socket substantially aligned with the center point of the fluorescent tube). For example, these sockets 42a, 42b, may be KULKA brand lamp sockets Cat. No. 582, 660 W-600 V/1000 V, available from Voltarc Technologies, Inc., 400 Captain Neville Drive, Waterbury, Conn. 06705, USA. The sockets 42a, 42b are mounted on oppositely disposed sidewalls 26a, 26b of the cabinet 22. These sidewalls 26a, 26b may be of variable thickness to define wireways or raceways, which accommodate electrical hardware (wiring) for the sockets 42a, 42b. At least one of the sockets, shown here as socket 42a mounted on sidewall 26a, is spring loaded (depressably mounted) by a spring mechanism, to allow for easy fluorescent tube 30 removal, by depressing the spring loaded socket 42a.
The arrangement of the fluorescent tubes 30 in the cabinet 22 of the sign 20, determines the internal cabinet depth (d), that serves to establish the overall sign depth (D). The internal cabinet depth (d) is less than the overall sign depths (D), as this overall depth (D) accounts for the thickness of the cabinet rear wall 25, any retainer portions that do not overlap with the cabinet body 24 (the non-overlapping portions of the retainer 34 including the graphic unit 32). This internal depth "d" is a combination of two distances, "d.sub.1 ", the cabinet rear wall to socket center/fluorescent tube (light) center distance, and "d.sub.2 ", the socket center/fluorescent tube center to diffuser panel 38 distance.
The distance (d.sub.1) between the rear wall 25 and the socket center/fluorescent tube center is determined by the distance needed to separate the fluorescent tube 30 from the cabinet rear wall 25. This distance (d.sub.1) is based on socket dimensions and safety concerns. For example, this distance may be approximately 1.1875 inches (3.02 cm) or greater.
The distance between the socket center/fluorescent tube center and the diffuser panel (d.sub.2) is in accordance with industry standards. It is the distance between the socket center/light center and the diffuser panel 38, where the light diffuses uniformly throughout the cabinet 22, such that: 1) the viewer sees the graphic illuminated at a uniform intensity distribution, as opposed to areas of greater intensity, known as "hot spots" and lesser intensity, known as "shadows"; and 2) the viewer has difficulty in determining the direction of the fluorescent tubes (lights) 30 in the cabinet 22. Typically, this distance is approximately 4 inches.
The combined distances, the sum of which is the respective internal cabinet depth, d, for the sign 20 is greater than four inches (due largely in part to the d.sub.2 distance of approximately 4 inches), whereby the overall cabinet depth D, for the sign 20, is also greater than four inches. The resultant sign 20, when mounted on a wall 21 or the like, extends (protrudes) more than four inches therefrom, and is thus, commonly referred to and classified as "high profile."
"High profile" signs, such as the sign 20 shown, exhibit substantial drawbacks. The "high profile" cabinet does not conform with the Americans With Disabilities Act Of 1990 (ADA), and in particular the ADA, at 36 CFR XI (7-1-96 Edition), Pt. 1191, App. A, Section 4.4.1. This section requires that "Objects projecting from walls with their leading edges between 27 and 80 in (685 mm and 2030 mm) above the finished floor shall protrude no more than 4 in (100 mm) [(100 mm as converted by the ADA)] into walks, halls, corridors, passageways, or aisles."
The technology associated with the conventional sign 20 and the like, is not suitable with "low profile" signs, as "low profile" signs extend not greater than approximately four inches from walls. This is because simply decreasing the distance between the socket center/fluorescent tube center and the diffuser panel (d.sub.2), does not allow for the uniform diffusion necessary for proper aesthetics. Rather, the diffusion and subsequent light distribution in the cabinets would be uneven, resulting in unaesthetic hot spots and shadows. Moreover, the viewer could easily visibly distinguish the direction of the fluorescent tubes in the cabinet.
To conform with the ADA, this conventional "high profile" sign 20, and others like it, with cabinets of greater than four inch depths, must be placed into the walls, by cutting the walls and setting the cabinets back into them. This retrofitting is expensive and destructive to the walls, and should the wall be a structural or load bearing wall, this retrofitting is not possible.